Are MRSA Antibiotics Overprescribed for Community-Acquired Pneumonia? – NEJM Journal Watch
Nearly 30% of hospitalized CAP patients received antibiotics for MRSA, even though fewer than 1% had MRSA-associated CAP.
A recent multicenter, prospective, active-surveillance study of 2259 patients hospitalized with CAP in Illinois and Tennessee between 2010 and 2012 determined that Staphylococcus aureus and, particularly, methicillin-resistant S. aureus (MRSA) seldom cause community-acquired pneumonia (CAP). However, many clinicians empirically treat CAP with the anti-MRSA antibiotics vancomycin and linezolid anyway.
This study used bacterial tests of blood and high-quality sputum samples, urinary antigen tests, and nucleic acid amplification tests of oropharyngeal swabs to determine the etiologic agents in CAP. S. aureus CAP was defined as detection of S. aureus from a respiratory or blood specimen.
The study determined that only 1.6% of CAP patients had S. aureus CAP and only 0.7% had MRSA CAP. The risk factors for S. aureus CAP was the need for chronic hemodialysis, presence of diabetes, and more severe pneumonia. Vancomycin or linezolid was prescribed initially in about 30% of all CAP patients.
We have to be more selective when choosing empiric antibiotics for different infections like CAP. Empiric MRSA coverage is generally not indicated unless the patient has risk factors for MRSA (post-influenza pneumonia, need for mechanical ventilation, history of IVDU, cavitary pneumonia, and chronic hemodialysis). Antibiotic stewardship programs should help to curb unnecessary broad-spectrum antibiotics for hospitalized conditions such as CAP.
Self WH et al. Staphylococcus aureus community-acquired pneumonia: Prevalence, clinical characteristics, and outcomes. Clin Infect Dis 2016 Aug 1; 63:300